JP7197325B2 - Pure water production device and pure water production method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pure water production apparatus and the like, and more particularly to a pure water production apparatus and the like for producing pure water such as pharmaceutical purified water.

For example, it is decided to use pharmaceutical purified water for manufacturing pharmaceuticals. This pharmaceutical purified water may be produced using an EDI (Electrodeionization: continuous electroregenerative deionization device) unit. In addition, pharmaceutical purified water is sometimes produced by desalting with an ion exchange resin device filled with an ion exchange resin.

In Patent Document 1, an electrodeionization apparatus is formed by arranging a plurality of anion exchange membranes and cation exchange membranes between a cathode and an anode to form a deionization chamber and a concentration chamber. and/or that the concentration compartment is filled with an open-celled foam containing a finely divided ion exchanger.

JP 2008-284488 A

However, when an EDI unit is used, power consumption is large, and the cost of producing pure water tends to increase. In addition, the EDI unit has a complicated internal structure and requires a large amount of money when introducing equipment and performing maintenance. On the other hand, in the case of ion-exchange resin devices, it is usually necessary to use chemicals when regenerating the ion-exchange resin. However, if the pure water is pharmaceutical purified water, it is necessary to avoid contamination with chemicals. Therefore, the entire ion-exchange resin may be replaced without regeneration, and in this case also, the cost of producing pure water tends to increase.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a pure water production apparatus or the like which does not have a complicated structure and which tends to reduce the cost of producing pure water.

Thus, according to the present invention, there are provided filtration and desalination means for obtaining permeated water by passing raw water through a reverse osmosis membrane, desalination means for desalinating permeated water by passing it through an ion exchange resin, and ion exchange resin. and a regenerating means for passing hot water through the water purifying apparatus.

Here, the ion exchange resin is a mixture of a cation exchange resin and an anion exchange resin, and whether the cation exchange resin has a strongly acidic exchange group or the anion exchange resin has a strongly basic exchange group is preferably at least one of In this case, desalination can be made higher.
In addition, the cation exchange resin has a strongly acidic exchange group, and the anion exchange resin has a weakly basic exchange group. It is preferable to make it smaller than . In this case, the efficiency of regeneration of the ion exchange resin can be further improved.
Furthermore, the cation exchange resin has a weakly acidic exchange group, and the anion exchange resin has a strongly basic exchange group, and the exchange capacity of the weakly acidic exchange group is the exchange capacity of the strongly basic exchange group. is preferably greater than . In this case, the efficiency of regeneration of the ion exchange resin can be further improved.
Moreover, it is preferable to further provide a first heating means for heating the permeated water to make it into hot water. In this case, the ion exchange resin can be regenerated with hot water from the first heating means.
Further, it is preferable to further include second heating means for heating the raw water. In this case, the raw water can be brought to a temperature that improves the performance of the downstream equipment, and the downstream equipment and piping can be thermally sterilized.
Moreover, it is preferable to further provide activated carbon treatment means for removing impurities with activated carbon between the second heating means and the filtering and desalting means. In this case, impurities contained in raw water can be removed.
Further, it is preferable that the desalting means and the regeneration means are one packed tank filled with an ion exchange resin to perform both treatments. In this case, the process of regenerating the ion exchange resin can be performed more easily.
Furthermore, the conductivity of permeated water is preferably 50 μS/cm or less. In this case, if this range is exceeded, the ion exchange resin is not efficiently regenerated.

Furthermore, according to the present invention, there are provided a filtration desalination step in which permeated water is obtained by passing raw water through a reverse osmosis membrane, and desalinization by passing permeated water through an ion exchange resin when producing pure water. A method for producing pure water is provided, which includes a desalting step, and a regeneration step of passing hot water through the ion exchange resin when regenerating the ion exchange resin.

Here, when regenerating the ion exchange resin, it is preferable to further include a heating step of heating the permeated water to make it into hot water. In this case, the hot water necessary for regenerating the ion exchange resin can be produced.
Moreover, it is preferable to further include a heating step of heating the raw water. In this case, the raw water can be brought to a temperature that improves the performance of the subsequent device. Further, between the heating step and the filtering and desalting step, an activated carbon treatment step for removing impurities with activated carbon can be further provided. is preferred. In this case, impurities contained in raw water can be removed.

Advantageous Effects of Invention According to the present invention, it is possible to provide a pure water production apparatus or the like that does not have a complicated structure and that tends to reduce costs when producing pure water.

It is a figure explaining the purified water production unit to which this Embodiment is applied. 4 is a flow chart explaining the operation of the purified water production unit when producing pharmaceutical purified water. 4 is a flow chart explaining the operation of the purified water production unit when regenerating the ion exchange resin. 4 is a flow chart explaining the operation of the purified water production unit when thermally sterilizing the devices from the activated carbon tower to the deaerator. 4 is a flow chart explaining the operation of the purified water production unit 1 when thermally sterilizing the devices from the ion exchange device to the ultrafiltration device. FIG. 4 is a diagram showing the results of Example 1; FIG. 10 is a diagram showing the results of Example 2; FIG. 10 is a diagram showing the results of Example 3; FIG. 10 is a diagram showing the results of Example 4; FIG. 10 is a diagram showing the results of Example 5; FIG. 10 is a diagram showing the results of Example 6; FIG. 10 is a diagram showing the results of Example 7; FIG. 10 is a diagram showing the results of Example 8; FIG. 11 is a diagram showing the results of Example 9;

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth, embodiment of invention) for implementing this invention is demonstrated in detail. It should be noted that the present invention is not limited to the following embodiments, and can be modified in various ways within the scope of the gist of the present invention. Also, the drawings used are for explaining the present embodiment and do not represent the actual size.
A pharmaceutical purified water manufacturing apparatus to which the present embodiment is applied will be described below with reference to the drawings.

<Overall description of purified water production unit 1>
FIG. 1 is a diagram illustrating a purified water production unit 1 to which this embodiment is applied.
The illustrated purified water production unit 1 is an example of a pure water production device. Purified water production unit 1 of the present embodiment is a device that purifies raw water to produce pharmaceutical purified water.

In the present embodiment, the raw water is, for example, normal water specified in the pharmaceutical monographs of the Japanese Pharmacopoeia. This ordinary water is required to conform to water quality standards based on Article 4 of the Water Supply Law. More specifically, the 2003 Ordinance of the Ministry of Health, Labor and Welfare No. 101 stipulates 50 items as water quality standards. In addition to this standard, ammonium is required to conform to the standard of "0.05 mg/L or less". The raw water is not limited to this, and may be industrial water or the like.

As ordinary water, for example, tap water or disinfected well water is used. Therefore, ordinary water usually contains free chlorine resulting from the chlorine agent used for disinfection. For example, sodium hypochlorite (NaClO) is used as the chlorine agent. Free chlorine resulting from this includes hypochlorous acid (HOCl), hypochlorous acid ion (OCl ⁻ ), and the like.

In the present embodiment, the pharmaceutical purified water is water for pharmaceutical use, and is purified water specified in each article of the Japanese Pharmacopoeia. This purified water has a total organic carbon (TOC) of 500 μg/L (ppb) or less and a conductivity (25° C.) of 1.3 μS/cm or less. There must be Purified water is used for manufacturing drug substances, dissolving agents in formulations, cleaning pharmaceutical equipment, adjusting reagent test solutions, cleaning medical equipment, adjusting cleaning agents and preservatives for contact lenses, and the like.

As shown, the purified water production unit 1 includes a raw water tank 10 for storing raw water, a heating device 20 for adjusting the temperature of the raw water, an activated carbon tower 30 for removing free chlorine contained in the raw water, and an activated carbon tower 30. A safety filter 40 that removes solids from the passed raw water, an RO (Reverse Osmosis Membrane) device 50 that purifies the raw water, a degassing device 60 that performs degassing, and heats the degassed water. A heater 70 for water, an ion exchange device 80 for desalting with an ion exchange resin, an ultrafiltration device 90 for removing solid matter, a storage tank 100 for storing the purified pharmaceutical water after purification, and a control unit 110 that controls the entire purified water production unit 1 .

The raw water tank 10, the heating device 20, the activated carbon tower 30, the safety filter 40, the RO device 50, the degassing device 60, the heater 70, the ion exchange device 80, the ultrafiltration device 90, and the storage tank 100 are made of stainless steel or resin. etc. are connected in series by pipes H1, H2, H3, H4, H5, H6, H7, H8, H9. Further, blow pipes B1, B2, and B3 branching from these pipes are arranged in the pipe H6, the pipe H8, and the pipe H9, respectively. Although details will be described later, the blow pipes B1, B2, and B3 are provided for blowing and discarding the hot water used for heat sterilization when heat sterilizing each device and pipes. The blow pipes B1, B2, and B3 are provided with valves (not shown), and by opening the valves, hot water can be blown from the blow pipes B1, B2, and B3. A pump P2 for supplying pharmaceutical purified water from the storage tank 100 is also provided.

When tap water is used as raw water, the tap water already has a predetermined water pressure, and using this water pressure, the raw water first enters the raw water tank 10 . Also, if the raw water does not have a predetermined water pressure, a separate pump or the like is prepared to put the raw water into the raw water tank 10 .

The raw water tank 10 temporarily stores raw water. By driving the pump P1, the raw water is delivered from the raw water tank 10 to the subsequent device.

The heating device 20 is an example of second heating means for heating the raw water, and is, for example, a device provided with a heat exchanger. By supplying steam, for example, to the heat exchanger, heat is exchanged with the raw water to heat the raw water. The temperature of raw water is, for example, 10°C. During normal operation, the heating device 20 heats the raw water to, for example, 25° C. to improve the performance of the reverse osmosis membrane (RO membrane) of the RO device 50, which will be described later.

Further, by using the heating device 20, it is possible to thermally sterilize the devices and pipes in the latter stage. At this time, the heating device 20 heats the raw water to, for example, 85° C. and supplies it as hot water. This heat sterilizes the equipment and piping. Since free chlorine remains in the raw water in the raw water tank 10 without being removed in the raw water tank 10, the raw water tank 10 does not need to be sterilized. On the other hand, although the details will be described later, since free chlorine is removed in the activated carbon tower 30, it is necessary to periodically sterilize the devices and pipes downstream of the heating device 20. FIG.

The activated carbon tower 30 is an example of activated carbon treatment means, and is a device filled with activated carbon. In this embodiment, the activated carbon tower 30 is arranged between the heating device 20 and the RO device 50 . By passing the raw water through the activated carbon, impurities such as free chlorine contained in the raw water are removed. The activated carbon used in the activated carbon tower 30 is not particularly limited. For example, activated carbon is roughly classified into coal-based activated carbon and coconut shell activated carbon depending on the raw material for producing activated carbon, and both can be used. However, it is preferable that the amount of impurities contained in the activated carbon is as small as possible in order to reduce the possibility of elution.

Note that any device other than the activated carbon tower 30 may be used as long as it has a function of removing free chlorine contained in raw water. For example, it may be a device that reduces free chlorine in raw water using sodium sulfite or a device that decomposes free chlorine by irradiation with ultraviolet rays.

The safety filter 40 removes solids such as fine particles. In the case of this embodiment, fine particles of activated carbon may be generated in the activated carbon tower 30 . Since fine particles of activated carbon may clog the reverse osmosis membrane when water is passed through the RO device 50 in the subsequent stage, the fine particles of activated carbon are removed in advance by the safety filter 40 .

The RO device 50 is an example of filtering and desalting means, and is a device provided with a reverse osmosis membrane (RO membrane). The RO device 50 passes raw water through a reverse osmosis membrane to filter impurities contained in the raw water, purify the raw water, and obtain permeated water. In addition, the reverse osmosis membrane performs rough desalting before desalting in the ion exchange device 80 .
A reverse osmosis membrane is a membrane in which a large number of pores with a size of approximately 1 nm to 2 nm are formed, and has the property of permeating water but not ions. Therefore, impurities such as salts and ions can be removed from raw water for purification. Examples of reverse osmosis membranes include polyamide membranes.

A degassing device 60 is provided to remove gaseous components such as carbon dioxide contained in water. The inside of the degassing device 60 is in a reduced pressure state, which is almost a vacuum. Therefore, by circulating the permeated water, the carbon dioxide dissolved in the permeated water can be degassed and separated from the permeated water.

The heater 70 is an example of a first heating means, and heats the permeated water when regenerating the ion exchange resin to obtain hot water. The heater 70 is, for example, a device that includes a heat exchanger. Then, by supplying, for example, steam to the heat exchanger, heat is exchanged with the permeated water to heat the permeated water.
Further, by using the heater 70, it is possible to thermally sterilize the devices and pipes in the latter stage. At this time, the heater 70 heats the permeated water to, for example, 85° C. and supplies it as hot water. As a result, equipment and piping can be heat sterilized.

The ion exchange device 80 is filled with an ion exchange resin. The ion exchange device 80 is an example of desalting means, and performs desalting by passing permeated water through an ion exchange resin when manufacturing purified water for pharmaceuticals. In this case, the conductivity of the permeated water discharged from the RO device 50 and treated by the ion exchange device 80 is 50 μS/cm or less. In the present embodiment, an ion-exchange resin that can be thermally regenerated is used to treat several thousand ppm of raw water such as seawater, which has been conventionally performed, and desalting some salts. Desalination is performed on permeated water with a low concentration of salts.

Regeneration means for regenerating the ion exchange resin may be provided at the same time as the desalting means. Specifically, the ion exchange device 80 is an example of regenerating means, and when regenerating the ion exchange resin, hot water is passed through the ion exchange resin. In other words, the ion exchange apparatus 80 of the present embodiment performs both the desalination process performed when producing pharmaceutical purified water and the regeneration process performed when regenerating the ion exchange resin in one packed tank. . Therefore, compared with the case where the ion-exchange resin is regenerated using chemicals after the ion-exchange resin is discharged from the tank, there is no need to take in and out the ion-exchange resin. Therefore, the process of regenerating the ion exchange resin can be performed more easily. Here, when desalting and regeneration are performed in one packed tank, the ion exchange device 80 is also called a desalting polisher for hot water regeneration. When desalting and regeneration are performed in separate tanks, regeneration means for regenerating the ion exchange resin may be provided immediately after the ion exchange device 80, which is the desalination means.
As a method for regenerating the ion-exchange resin, the direction of hot water flowing through the desalting polisher may be either downward flow or upward flow, but upward flow is preferred. Further, as the regeneration means, a tank for performing regeneration in an upward flow may be provided immediately after the desalination means.

The ultrafiltration device 90 is provided to remove fine solids contained in pure water. For this purpose, an ultrafiltration membrane (UF membrane) is provided inside the ultrafiltration device 90 . The ultrafiltration membrane is, for example, a membrane made of polyamide or polysulfone and provided with a large number of pores having a size of 2 nm to 200 nm. By passing through this membrane, solid matter such as fine particles can be removed.

The storage tank 100 stores water that has passed through the ultrafiltration device 90 and has become pharmaceutical purified water. Then, the pharmaceutical purified water is sent from the storage tank 100 to the point of use by driving the pump P2.

<Description of ion exchange device 80>
Next, the ion exchange device 80 will be described in more detail.
In this embodiment, the ion exchange resin filled in the ion exchange device 80 is regenerated by passing hot water through the ion exchange resin. That is, no chemical such as hydrochloric acid or sodium hydroxide is used when regenerating the ion exchange resin. As a result, when producing pure water such as pharmaceutical purified water, it is possible to prevent chemicals remaining in the ion-exchange resin after regeneration from being mixed into the product.

When hot water is passed through the ion-exchange resin, the following thermal regeneration (dissociation of water) phenomenon occurs, whereby regeneration can be performed. This regeneration method takes advantage of the difference in the dissociation constants of hydrogen ions (H ⁺ ) and hydroxide ions (OH ⁻ ) at low and high temperatures of water. That is, water dissociates as shown below.

H ₂ O ←→ H ⁺ + OH ⁻

At this time, the dissociation constant Kw is Kw=1.023×10 ⁻¹⁴ at a low temperature of 25° C., for example. On the other hand, for example, at a high temperature of 75° C., Kw=19.95×10 ⁻¹⁴ . In other words, the higher the temperature, the more the amount of H ⁺ and OH ⁻ produced because the equilibrium shifts toward the right side.

When this phenomenon is applied to an ion exchange resin, the salts are adsorbed to the ion exchange resin by passing low-temperature water through the resin. At high temperatures, the dissociated H ⁺ and OH ⁻ increase, so they act as regenerants for the ion exchange resin. Therefore, by passing high-temperature water (hot water), the salts can be desorbed and the ion exchange resin can be regenerated.

Here, the hot water to be used preferably has an outlet temperature of 50° C. or higher when the water is passed through the ion exchange device 80 . When the temperature is less than 50°C, the thermal regeneration phenomenon hardly occurs, making it difficult to regenerate the ion exchange resin. Moreover, from the viewpoint of not only regenerating the ion exchange resin but also heat sterilizing the inside of the ion exchange device 80, the temperature of the hot water is preferably 60° C. or higher. If the temperature is less than 60°C, heat sterilization becomes difficult. Furthermore, with respect to the regeneration and heat sterilization of the ion exchange resin, the higher the temperature, the better the effect. However, when the temperature approaches 100° C., the water turns into gas and air bubbles are generated, which causes excessive agitation of the ion exchange resin and makes regeneration of the ion exchange resin difficult. Also, from the viewpoint of the heat resistance of the ion exchange resin, the temperature is preferably low, and specifically, it is preferably 90° C. or less. That is, when the temperature exceeds 90°C, the ion exchange resin tends to be eluted. From the above, the hot water preferably has an outlet temperature of 50 ° C. or higher and lower than 100 ° C., more preferably 60 ° C. or higher and 90 ° C. or lower, around 80 ° C. (e.g., 80 ° C. ± 5 ° temperature range) is particularly preferred. Since the hot water is cooled when it is passed through the ion exchange device 80, when the outlet temperature of the hot water is 80°C, the inlet temperature is 85°C, for example.

The ion exchange apparatus 80 of the present embodiment is a mixed-bed ion exchange tower. That is, the ion-exchange resin filled inside is in a state of being a mixture of the cation-exchange resin and the anion-exchange resin. The ion-exchange resin is preferably in the form of particles, and can be, for example, pellets molded into a cylindrical shape, a spherical shape, or the like. Further, when the ion exchange resin is classified by degree of cross-linking or porosity, gel type, porous type, high porous type, etc. can be mentioned, and any of them can be used.

The ion exchange resin of the present embodiment preferably has at least one of a cation exchange resin having a strongly acidic exchange group and an anion exchange resin having a strongly basic exchange group. That is, it is preferable that the exchange group of the cation exchange resin + the exchange group of the anion exchange resin be any combination of strong acidity + strong basicity, strong acidity + weak basicity, or weak acidity + strong basicity. At this time, the combination of weakly acidic + weakly basic is not included. A weakly acidic + weakly basic combination makes it difficult to remove neutral salts from the permeated water, and the desalting property tends to be lower than other combinations. Examples of neutral salts include NaCl, CaCl ₂ , Na ₂ SO ₄ and the like. Conventionally, heat-regenerative ion exchange resins have been a combination of weakly acidic + weakly basic as exchange groups for cation exchange resins + exchange groups for anion exchange resins. On the other hand, the present embodiment differs in that the combination of strong acidity + strong basicity, strong acidity + weak basicity, and weak acidity + strong basicity is more preferable.

Strongly acidic exchange groups include sulfonic acid groups (--SO ₃ H). A carboxyl group (--COOH) may be mentioned as the weakly acidic exchange group.
Examples of the strongly basic exchange group include a trimethylammonium group, which is a quaternary ammonium group, and a dimethylethanolammonium group. Furthermore, weakly basic exchange groups include primary to tertiary amino groups.

In the case of a combination of strong acidity and weak basicity as the exchange group of the cation exchange resin + the exchange group of the anion exchange resin, the exchange capacity of the strongly acidic exchange group is smaller than the exchange capacity of the weakly basic exchange group. is preferred. This is because the equivalent ratio of the exchange capacity of the strongly acidic exchange group and the exchange capacity of the weakly basic exchange group is such that the exchange capacity of the strongly acidic exchange group: the exchange capacity of the weakly basic exchange group = 1: x (x >1).

In this case, when the ion exchange resin is regenerated, the anion component adsorbed to the weakly basic exchange group is more likely to be desorbed than the cation component adsorbed to the strongly acidic exchange group. In this case, the cation is, for example, Na+ (sodium ion) and the anion is, for example, Cl ⁻ (chloride ion). At this time, Cl ⁻ becomes HCl (hydrochloric acid) together with H ⁺ (hydrogen ion) in water, and this desorbs the cationic component adsorbed on the strongly acidic exchange group. Therefore, this phenomenon is promoted by making the exchange capacity of the strongly acidic exchange group smaller than the exchange capacity of the weakly basic exchange group. As a result, the regeneration efficiency of the ion exchange resin is improved.

On the other hand, when the exchange group of the cation exchange resin + the exchange group of the anion exchange resin is a combination of weak acidity and strong basicity, the exchange capacity of the weakly acidic exchange group is higher than that of the strongly basic exchange group. Large is preferred. This is because the equivalent ratio of the exchange capacity of the weakly acidic exchange group and the exchange capacity of the strongly basic exchange group is such that the exchange capacity of the weakly acidic exchange group: the exchange capacity of the strongly basic exchange group = 1: y (y <1) can also be said.

In this case, when the ion exchange resin is regenerated, the cationic component adsorbed to the weakly acidic exchange group is more likely to be desorbed than the anionic component adsorbed to the strongly basic exchange group. In this case, for example, when the cation is Na ⁺ , it becomes NaOH (sodium hydroxide) together with OH ⁻ (hydroxide ion) in water, and this desorbs the anion component adsorbed on the strongly basic exchange group. Let Therefore, by making the exchange capacity of the weakly acidic exchange group larger than the exchange capacity of the strongly basic exchange group, this phenomenon is promoted and the regeneration efficiency of the ion exchange resin is improved.

<Explanation of operation of purified water production unit 1>
Next, the operation of the purified water production unit 1 will be explained. The operation of the purified water production unit 1 described below can also be regarded as a pure water producing method for producing pure water such as pharmaceutical purified water.

FIG. 2 is a flow chart explaining the operation of the purified water production unit 1 when producing pharmaceutical purified water.
First, raw water is introduced into the raw water tank 10 and temporarily stored in the raw water tank 10 (step 101: raw water storage step).

Then, the pump P1 is used to send the raw water to the subsequent device. In this case, the raw water is first heated by the heating device 20 to a temperature suitable for water treatment by the subsequent RO device 50 or the like (step 102: heating step). This temperature is, for example, 25°C.
Next, in the activated carbon tower 30, impurities such as free chlorine in the raw water are removed by activated carbon (step 103: activated carbon treatment step). Furthermore, solids such as fine particles in the raw water are removed by the safety filter 40 (step 104: fine particle removal step).

Then, the raw water is passed through the reverse osmosis membrane in the RO device 50 to obtain permeated water (step 105: filtration and desalination step).
Further, carbon dioxide is deaerated by the deaerator 60 (step 106: deaeration step), and the ion exchange device 80 is used to demineralize the permeated water by passing it through the ion exchange resin (step 107). : desalting process). Note that the heater 70 is not used when pure water is produced, and the permeated water passes through the heater 70 without being heated.
Then, solid content is removed by the ultrafiltration device 90 (step 108: solid content removal step), and the manufactured pharmaceutical purified water is stored in the storage tank 100 (step 109: purified water storage step).
Purified water for pharmaceuticals can be produced by the above steps.

FIG. 3 is a flow chart explaining the operation of the purified water production unit 1 when regenerating the ion exchange resin.
Conductivity is generally used as an index for determining whether or not to regenerate the ion exchange resin. That is, a standard is set for the conductivity of the outlet water of the ion exchange device 80 when pure water is produced, and when the standard is reached, the ion exchange resin is regenerated. This conductivity varies depending on the quality required for pure water, but is, for example, 1.0 μS/cm.

Steps 201 to 206 shown in the figure are the same as steps 101 to 106 in FIG. 2, so description thereof will be omitted.
After step 207, the heater 70 heats the permeated water to obtain hot water (step 207: heating step). The temperature of hot water is, for example, 85°C.
Next, hot water is passed through the ion exchange resin in the ion exchange device 80 to regenerate the ion exchange resin (step 208: regenerating step).
The hot water after passing through the ion exchange resin is discharged from the blow pipe B2 (step 209: regeneration blow step).
Through the steps described above, the ion exchange resin in the ion exchange device 80 can be regenerated.

Next, the process of heat sterilization will be described. When pharmaceutical purified water is produced as pure water, it is necessary to periodically heat-sterilize the inside of the device and the pipes in order to suppress the growth of bacteria in the device.
There are two types of thermal sterilization: one is to thermally sterilize the front-stage equipment from the activated carbon tower 30 to the degassing device 60, and the other is to thermally sterilize the rear-stage equipment from the ion exchange device 80 to the ultrafiltration device 90. be.

FIG. 4 is a flow chart explaining the operation of the purified water production unit 1 when the devices from the activated carbon tower 30 to the deaerator 60 are thermally sterilized.
The illustrated step 301 is similar to step 101 of FIG.
After step 302, the heating device 20 heats the raw water to make hot water (step 302: raw water heating step). The temperature of hot water is, for example, 85°C.
Next, hot water is passed through the activated carbon tower 30 to thermally sterilize the inside of the activated carbon tower 30 (step 303: activated carbon tower sterilization step).

Further, hot water is passed through the safety filter 40 to thermally sterilize the inside of the safety filter 40 (step 304: safety filter sterilization step).
Then, hot water is passed through the RO device 50 to thermally sterilize the inside of the RO device 50 (step 305: RO device sterilization step). is heat sterilized (step 306: deaerator sterilization step).
The hot water that has passed through the deaerator 60 is discharged from the blow pipe B1 (step 307: pre-stage sterilization blow step).
Through the steps described above, the devices on the upstream side from the activated carbon tower 30 to the degassing device 60 can be thermally sterilized.

FIG. 5 is a flow chart explaining the operation of the purified water production unit 1 when the devices from the ion exchange device 80 to the ultrafiltration device 90 are thermally sterilized.
The illustrated steps 401-407 are similar to steps 201-207 of FIG.
After step 408, hot water is passed through the ion exchange device 80 to thermally sterilize the inside of the ion exchange device 80 (step 408: ion exchange device sterilization step).
Next, hot water is passed through the ultrafilter 90 to thermally sterilize the inside of the ultrafilter 90 (step 409: ultrafilter sterilization step).
After passing through the ultrafiltration device 90, the hot water is discharged from the blow pipe B3 (step 410: post-sterilization blow step).
Through the steps described above, the downstream devices from the ion exchange device 80 to the ultrafiltration device 90 can be thermally sterilized.

According to the purified water production unit 1 described above, water is passed through the ion exchange resin in the ion exchange device 80 when producing pure water. Therefore, compared with the case of using EDI, it does not have a complicated structure, and the cost for introducing equipment and performing maintenance is low. Moreover, compared to EDI, the power consumption is very low. As a result, it is possible to provide a pure water production apparatus that tends to reduce the cost of producing pure water.

Also, when the ion exchange resin is regenerated, hot water may be passed through the ion exchange device 80 . Therefore, compared with the case where the ion exchange resin is regenerated using chemicals, the cost required for regeneration can be reduced. Furthermore, since it is possible to prevent contamination of chemicals used for regeneration, the purified water producing unit 1 of the present embodiment is effective when producing pure water, especially pharmaceutical purified water. Furthermore, conventionally, when manufacturing purified water for pharmaceuticals, it is difficult to use chemicals, so it has been common practice to dispose of the ion-exchange resin without regenerating it. According to the purified water producing unit 1 of the present embodiment, the ion exchange resin can be regenerated with hot water, so the cost for producing pharmaceutical purified water tends to be lower.

In the purified water production unit 1 described above, the case of producing pharmaceutical purified water as pure water has been explained, but it is of course applicable to the case of producing pure water used for purposes other than pharmaceutical purified water. be. In this case, heat sterilization of the equipment and piping may not be required. At this time, for example, the heating device 20 may become unnecessary. Also, if tap water is not used as raw water and there is no need to remove free chlorine, the activated carbon tower 30 may not be required. Furthermore, when the activated carbon tower 30 is not required, the safety filter 40 may not be necessary because the safety filter 40 does not need to remove fine particles of the activated carbon. Furthermore, since the carbon dioxide in the raw water can also be removed by the anion exchange resin in the ion exchange device 80, the degassing device 60 may not be necessary as long as the burden on the anion exchange resin is not excessive. . Further, if the ion exchange resin in the ion exchange device 80 can be regenerated with hot water heated by the heating device 20, the heater 70 may be unnecessary. However, either one of the heating device 20 and the heater 70 is required to regenerate the ion exchange resin. Furthermore, the ultrafiltration device 90 may not be necessary if there is no need to remove solids at the end of the series of steps.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples as long as it does not exceed the scope of the invention.
In the following examples, the ion exchange resins used are as follows, all of which are manufactured by Mitsubishi Chemical Corporation.

Strongly acidic cation exchange resin: SK1B
Weakly acidic cation exchange resin: WK11, WK40L
Strongly basic anion exchange resin: SA10A
Weakly basic anion exchange resin: WA20, WA30, WA21J (heat-resistant version of WA20)

(Example 1)
In Example 1, changes in electrical conductivity in water were investigated as the water temperature increased. Specifically, an ion exchange resin, which is a mixture of a cation exchange resin that adsorbs Na ⁺ as cations and an anion exchange resin that adsorbs Cl ⁻ ions as anions, is immersed in water of 10 μS/cm. The relationship between temperature and conductivity was investigated. The exchange groups of the cation exchange resin and the anion exchange resin, which are ion exchange resins, are strongly acidic + strongly basic (SS), strongly acidic + weakly basic (SW), and weakly acidic + strongly basic (WS). , weakly acidic + weakly basic (WW) combinations were used.

6 is a diagram showing the results of Example 1. FIG. In the figure, the horizontal axis represents the temperature of water, and the vertical axis represents the electrical conductivity of water.
As shown in the figure, the exchange group can be any one of strongly acidic + strongly basic (SS), strongly acidic + weakly basic (SW), weakly acidic + strongly basic (WS), and weakly acidic + weakly basic (WW). Also in the combination of , the conductivity of water increased as the water temperature increased. In other words, it is thought that when the temperature rises, more salts adsorbed on the ion exchange resin are desorbed and eluted into water, resulting in an increase in electrical conductivity. In this case, Na ⁺ is desorbed from the cation exchange resin and Cl ⁻ is desorbed from the anion exchange resin, resulting in an increase in electrical conductivity. This indicates that it is possible to regenerate these ion exchange resins with hot water.

(Example 2)
In Example 2, changes in pH in water were investigated as the water temperature increased. Specifically, the same combination of ion-exchange resins as in Example 1 was immersed in water of 10 μS/cm, and the relationship between water temperature and pH was examined.

7 is a diagram showing the results of Example 2. FIG. In the figure, the horizontal axis represents the temperature of water, and the vertical axis represents the pH of water.
As shown in the figure, the exchange group can be any one of strongly acidic + strongly basic (SS), strongly acidic + weakly basic (SW), weakly acidic + strongly basic (WS), and weakly acidic + weakly basic (WW). Also in the combination of , the result was that the pH did not change much as the water temperature increased.
At this time, the pH was almost neutral in the combination of strong acidity + strong basicity (SS) and weak acidity + weak basicity (WW).
However, strongly acidic + weakly basic (SW) resulted in an acidic pH. This indicates that the elimination of Cl ⁻ is more than that of Na ⁺ . That is, weakly basic anion-exchange resins show weaker bonds between salts and ion-exchange resins than strongly acidic cation-exchange resins, resulting in more desorption of adsorbed salts.
On the other hand, weakly acidic + strongly basic (WS) resulted in alkaline pH. It shows that the elimination of Na ⁺ is more than that of Cl ⁻ . That is, weakly acidic cation exchange resins show weaker binding between salts and ion exchange resins than strongly basic anion exchange resins, and more desorption of adsorbed salts.

(Example 3)
In Example 3, the thermal desorption rate was investigated. Specifically, the same combination of ion-exchange resins as in Example 1 was immersed in water at room temperature and in hot water at 80° C., and the amounts of Na ⁺ and Cl ⁻ desorbed were examined. The thermal desorption rate was calculated by The thermal desorption rate was calculated by the following formula. The thermal desorption rate is an index representing how much the ion exchange resin has been regenerated.

8 is a diagram showing the results of Example 3. FIG. In the figure, the horizontal axis represents the combination of ion exchange resins, and the vertical axis represents the thermal desorption rate.
As shown in the figure, the exchange group can be any one of strongly acidic + strongly basic (SS), strongly acidic + weakly basic (SW), weakly acidic + strongly basic (WS), and weakly acidic + weakly basic (WW). Also in the combination of , the amount of desorption increases when the water temperature is 80°C than at room temperature, indicating that regeneration is possible with hot water.

(Example 4)
In Example 4, the elution amount of the ion exchange resin was examined. Specifically, the same combination of ion exchange resins as in Example 1 was immersed in water at room temperature and in hot water at 80° C., and the TOC concentration was measured. When pharmaceutical purified water is produced as pure water, it is preferable that the ion exchange resin is not eluted as much as possible. As a standard, the TOC concentration is required to be 500 μg/L (ppb) or less.

9 is a diagram showing the results of Example 4. FIG. In the figure, the horizontal axis represents the combination of ion exchange resins, and the vertical axis represents the TOC concentration.
As shown in the figure, the exchange group can be any one of strongly acidic + strongly basic (SS), strongly acidic + weakly basic (SW), weakly acidic + strongly basic (WS), and weakly acidic + weakly basic (WW). , the TOC concentration was 40 μg/L (ppb) or less, satisfying the above criteria.

(Example 5)
In Example 5, it was verified whether or not the ion-exchange resin after regenerating with hot water has the adsorption capacity again. Specifically, an ion exchange resin was prepared by mixing a cation exchange resin that adsorbs Na ⁺ as cations and an anion exchange resin that adsorbs Cl ⁻ ions as anions. Then, as data before regeneration, it was immersed in water of 10 μS/cm, subjected to constant temperature shaking at room temperature for 24 hours, and the electrical conductivity was measured. As data after regeneration, the ion exchange resin was subjected to constant temperature shaking at 80° C. for 24 hours, and then at room temperature for 24 hours, and the electrical conductivity was measured.

10 is a diagram showing the results of Example 5. FIG. In the figure, the horizontal axis represents the combination of ion exchange resins, and the vertical axis represents the electrical conductivity.
As shown in the figure, in any combination of strongly acidic + weakly basic (SW), weakly acidic + strongly basic (WS), and weakly acidic + weakly basic (WW) exchange groups, the , a decrease in conductivity was confirmed. This indicates that regeneration with hot water at 80° C. caused desorption of Na ⁺ and Cl ⁻ adsorbed on the ion-exchange resin, resulting in a decrease in electrical conductivity. Then, it can be seen that the adsorption ability was restored by regeneration with hot water.

(Example 6)
In Example 6, as the exchange group of the cation exchange resin + the exchange group of the anion exchange resin, in the combination of strongly acidic + weakly basic (SW), the exchange capacity of the strongly acidic exchange group and the exchange group of the weakly basic exchange group When changing the ratio to the exchange capacity, changes in conductivity due to ions desorbed in hot water at 80° C. were measured.
In addition, as the exchange group of the cation exchange resin + the exchange group of the anion exchange resin, in the combination of weakly acidic + strongly basic (WS), the exchange capacity of the weakly acidic exchange group and the exchange capacity of the strongly basic exchange group The change in electrical conductivity due to ions desorbed in hot water at 80° C. was measured when the ratio of
In this case, the total exchange capacity of the cation exchange resin and the exchange capacity of the anion exchange resin is 26 meq.

11 is a diagram showing the results of Example 6. FIG. In the figure, the horizontal axis represents pH, and the vertical axis represents electrical conductivity.
As shown in the figure, in the combination of strongly acidic and weakly basic (SW) exchange groups, the conductivity is lower when the exchange capacity of the strongly acidic exchange group is smaller than the exchange capacity of the weakly basic exchange group. big. In addition, in the combination of weakly acidic and strongly basic (WS) exchange groups, the conductivity is higher when the exchange capacity of the weakly acidic exchange group is larger than the exchange capacity of the strongly basic exchange group.
In this case, the larger the conductivity, the larger the amount of salts desorbed from the ion exchange resin, which means that the efficiency of regeneration of the ion exchange resin is high.

(Example 7)
In Example 7, as the exchange group of the cation exchange resin + the exchange group of the anion exchange resin, in the combination of strongly acidic + weakly basic (SW), the exchange capacity of the strongly acidic exchange group and the exchange group of the weakly basic exchange group The thermal desorption rate was examined in the same manner as in Example 3 when the ratio to the exchange capacity was changed.
In addition, as the exchange group of the cation exchange resin + the exchange group of the anion exchange resin, in the combination of weakly acidic + strongly basic (WS), the exchange capacity of the weakly acidic exchange group and the exchange capacity of the strongly basic exchange group The rate of thermal desorption was examined in the same manner as in Example 3 when the ratio of

12 is a diagram showing the results of Example 7. FIG. In the figure, the horizontal axis represents the combination of ion exchange resins, and the vertical axis represents the thermal desorption rate.
As shown in the figure, in the combination of strongly acidic and weakly basic (SW) exchange groups, the exchange capacity of the strongly acidic exchange group is smaller than the exchange capacity of the weakly basic exchange group. rate is high. In addition, in the combination of weakly acidic + strongly basic (WS) exchange groups, the larger the exchange capacity of the weakly acidic exchange group than the exchange capacity of the strongly basic exchange group, the higher the thermal desorption rate. .
In this case, the higher the thermal desorption rate, the greater the amount of salts desorbed from the ion exchange resin, which means that the regeneration efficiency of the ion exchange resin is high.

(Example 8)
In Example 8, a column water flow test was performed using a combination of strongly acidic and weakly basic (SW) exchange groups. At this time, 57.2 mL-R of SK1B was used as the strongly acidic cation exchange resin, and 99.8 mL-R of WA21J was used as the weakly basic anion exchange resin. That is, the total amount of ion exchange resin is 157 mL-R. The equivalent ratio of these exchange capacities was SK1B:WA21J=1:1.5. Then, these ion exchange resins were packed in a column of 20 mmφ×1000 mmH with a layer height of 500 mmH.
Next, RO-treated water having a conductivity of 10 μS/cm was used as feed water, and water was passed through this column to examine the change in conductivity. At this time, water flow SV (Space Velocity) was set to 20 h ⁻¹ (≈50 mL/min).

13 is a diagram showing the results of Example 8. FIG. In the figure, the horizontal axis represents the water flow rate, and the vertical axis represents the electrical conductivity.
In this example, the target of the electrical conductivity of the water after treatment with the ion exchange resin was 1.0 μS/cm or less. Then, as shown in the figure, the water flow rate was 1.0 μS/cm at 7000 BV.

(Example 9)
In Example 9, the ion exchange resin used in Example 8 was regenerated with hot water at 80° C., and it was examined whether it could be reused.

14 is a diagram showing the results of Example 9. FIG. In the figure, the horizontal axis represents the water flow rate, and the vertical axis represents the electrical conductivity.
As shown in the figure, in the first water flow, the double water flow rate was 1.0 μS/cm at 7000 BV, as in Example 8. The water flow SV was set to 20 h ⁻¹ when the water flow rate was in the range of 0 BV to 1500 BV and 3200 BV to 7000 BV, and was set to 40 h ⁻¹ in the range of 1500 BV to 3200 BV. Then, the ion-exchange resin after passing water was regenerated with hot water at 80° C., and water was passed for the second time. As a result, the electrical conductivity of the water at the initial stage was 0.75 μS/cm, confirming that the regeneration was carried out. Then, at 232 BV, it became 1.0 μS/cm again.

1 Purified water production unit 10 Raw water tank 20 Heating device 30 Activated carbon tower 40 Safety filter 50 RO device 60 Degassing device 70 Heater 80 Ion exchange device 90... Ultrafiltration device, 100... Storage tank, 110... Control unit

Claims (12)

Filtration and desalination means for obtaining permeated water by passing raw water through a reverse osmosis membrane;
a desalting means for desalting the permeated water by passing it through an ion exchange resin;
regeneration means for passing hot water through the ion exchange resin;
A pure water production apparatus comprising
The ion exchange resin is a mixture of a cation exchange resin and an anion exchange resin,
The cation exchange resin has a strongly acidic exchange group, and the anion exchange resin has a weakly basic exchange group,
The pure water production apparatus, wherein the exchange capacity of the strongly acidic exchange group is smaller than the exchange capacity of the weakly basic exchange group. Filtration and desalination means for obtaining permeated water by passing raw water through a reverse osmosis membrane;
a desalting means for desalting the permeated water by passing it through an ion exchange resin;
regeneration means for passing hot water through the ion exchange resin;
A pure water production apparatus comprising
The ion exchange resin is a mixture of a cation exchange resin and an anion exchange resin,
The cation exchange resin has a weakly acidic exchange group, and the anion exchange resin has a strongly basic exchange group,
The pure water production apparatus, wherein the exchange capacity of the weakly acidic exchange group is larger than the exchange capacity of the strongly basic exchange group. 3. The pure water producing apparatus according to claim 1, further comprising a first heating means for heating said permeated water to make said hot water. 4. The pure water production apparatus according to claim 3 , further comprising second heating means for heating the raw water. 5. The pure water production apparatus according to claim 4 , further comprising activated carbon treatment means for removing impurities with activated carbon between said second heating means and said filtering and desalting means. 3. The pure water production apparatus according to claim 1, wherein said desalination means and said regeneration means are a single packed tank filled with said ion exchange resin for performing both treatments. 3. The pure water production apparatus according to claim 1, wherein said permeated water has a conductivity of 50 [mu]S/cm or less. a filtration and desalination step of obtaining permeated water by passing raw water through a reverse osmosis membrane;
a desalting step of passing the permeated water through an ion exchange resin to desalinate it when producing pure water;
a regeneration step of passing hot water through the ion exchange resin when regenerating the ion exchange resin;
A pure water production method comprising
The ion exchange resin is a mixture of a cation exchange resin and an anion exchange resin,
The cation exchange resin has a strongly acidic exchange group, and the anion exchange resin has a weakly basic exchange group,
A method for producing pure water, wherein the exchange capacity of the strongly acidic exchange group is smaller than the exchange capacity of the weakly basic exchange group. a filtration and desalination step of obtaining permeated water by passing raw water through a reverse osmosis membrane;
a desalting step of passing the permeated water through an ion exchange resin to desalinate it when producing pure water;
a regeneration step of passing hot water through the ion exchange resin when regenerating the ion exchange resin;
A pure water production method comprising
The ion exchange resin is a mixture of a cation exchange resin and an anion exchange resin,
The cation exchange resin has a weakly acidic exchange group, and the anion exchange resin has a strongly basic exchange group,
A method for producing pure water, wherein the exchange capacity of the weakly acidic exchange group is larger than the exchange capacity of the strongly basic exchange group. 10. The pure water producing method according to claim 8 , further comprising a heating step of heating the permeated water to make it into the hot water when regenerating the ion exchange resin. 11. The pure water production method according to claim 10 , further comprising a heating step of heating the raw water. 12. The method for producing pure water according to claim 11 , further comprising an activated carbon treatment step of removing impurities with activated carbon between said heating step and said filtering and desalting step.

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